修磨后的锯片在淬火架上应保证齿高（）的淬火部位。
A.1/2
B.1/3
C.2/3
D.1/4
参考答案：B
---Where does John live?
---He lives on ______ floor but he doesn’t use a lift to go up and down.
A．nine
B．the ninth
C．the nineth
D．a ninth
Gd-DTPA注射后，肝脓肿的脓腔的脓壁可呈()
A.双线征
B.花环征
C.牛眼征
D.灯泡征
E.晕环征
